Hearing aid device



June 29, 1943 E. c. NlcHoLlDEs l i HEARING AID DEVICE Filed July 11,l 19.40 2 sneaks-sheet 1 ATTQR J'ne 29,1943.

5.4. NlcHoLlDEs HEARING AID DEVICE 2 sheets-sheet 2 Filed July l1, 1940 mici "R It ls also an object of this Patented June 29, 1943 r a HEARING am nsvrca Emmanuel ola-lst Nielmlldes, Bronx, N. Y., assunor to Aurex Corporation,

- ration of Illinois Chicago, 1li., a corpo- Application July 11, 1940, serialNo. 344,853

' s claims` (ci. rvs-icmV This invention relates to a bone `conduction hearing aid deviceof the kind which includes a piezo-electric. crystal.

The crystal per se may be of the Rochelle salt or similar type and such crystals are at the present time standard articles `of commerce so will not be described in detail in this application, except to point out that` when an electric ileld is impressed upon such a crystal, it distorts and when a series of electric waves of varying frequencyv and amplitude are applied, it is set a device which is simple and rused in constnce tion so that it will be durable and resist ordinary jars and impacts to which it might be subjected to in use or by accident.

in vibratcy motion. Because of this characteristic, a piezo-electric crystal may be used to translate electric wave energy intc mechanical vibratory motion. y

In devices of this kind, sound waves are impressed upon a microphone or transmitter which serves to modify electric waves in accordance with the characteristics of the sound waves re ceived and then these electric waves are conducted to the piezo-electric crystal which translates the electrical energy into mechanical vibratory energy for direct communication to the bone structure of the head. y

A full description of the type of crystal used in devices of this kindand anY electric circuit commonly used in such hearing aid devices, is

shown and described in my Patent No. 2,045,403.

An object of the present invention is to construct a hearing aid device of the piezo-electric type designed so that a maximum of the vibratory energy of the crystal iscommunicated to the bone structure of the wearer.

lIt is also an object of this' invention to communicate with a minimum. oi' loss vibrations of such 'kind and quality as are found in ordinary speech and other common sounds.

A hearing aid device should be very small so ,that it will be inconspicuous when worn by the hard of hearing. On ,the other hand, the bone structure of the head possesses considerable mass and weight, and therefore, it is diilicult to communicate the vibrations of the very small mass to the very large mass without changing the vibratory characteristics or limiting to a great extentl the frequencies which can be transmitted, so it is an object of the present invention to produce a device which is small, light in weight and inconspicuous and yet powerful enough to transmit its vibratory energy to the head bone structure or other relatively heavy load, and especially to transmit those wavesand frequencies which produce the speech sounds and more common sounds of every day life. A

invention to produce Looking at the gures- Fig. 1 is a plan viewfof the device with the cover removed; l

Fig. 2 is a section through 2-2 of Fig. 1; Fig. 3 is a section through 3-3 of Fig. 1; Fig. 4 is a'section through 4-4 of Fig. 1; j Fig. 5 is a section through 5-5 of Fig. 1; Fig. 6 is a' section through 6-6 of Fig. 1;

of the elements of the device;

Fig. 8 is a section `through 8-8 of Fig. 7; Fig. 9 is a plan view of the diaphragm; and Fig. 10 is a side view of the diaphragm.

Looking at Figs. 1 to 6. Fig. 1 isl a base which may be made of plastic, hard rubber or other insulating material and on which the other elements of the device are mounted. A cover 2 Vis designed to cooperate with base I to make an enclosure for the various mechanical part-s of the device and it is held in place on base I by means of screws 3 and 4.

Mounted on the left end of base I as viewed in Figs. 1 to 3, is a piezo-electric crystal of 1aminated form shown at 4. The left end of crystal 4 as viewed in Figs. l to 3, is clamped` between clamping blocks 1 and 8. Block I is attached to base I and may even be .cast 8f pressed from the same material and made an integral part thereof. Blocks vI and 8 are designed to be held togther by screws III and I I.

Between blocks 1 and 8 one end of crystal 4 is iirmly held and the crystal is designed to extend outwardly from said clamping blocksin a more or less parallel relatio-nship with the base I so j Also held between the blocks 'I and l is an end portionI I6 ,of a lever I5 shown in detail in Figs. 7 and 8. The portion I6 is disposed under the crystal 4 -directly on top of the shoulders of block 1. It is formed with a downwardly projecting lip l1 designed to strengthen it, and it serves to bridge over the space immediately above the head of the screw I8 so as to form a continuous at surface to support the crystal 4.

Lever I5 when clamped in position projects outwardly from the clamping block 'I to the right as viewed in Fig. 2 in a more or less parallel relationship with the crystal 4 andthe base I.

Fig. 'I is a plan view of the lever which is one Y It also ls'supported as a cantilever with one end held' immovable while the other is free to move. Itis formed with upwardly turned side pieces 2| which serve to give it strength and rigidity. From the side pieces 2| are turned out projectling ears 22 and 23. 'Ihese as will be seen in Fig.

7, project transversely from the sides of the lever. They are designed to connect with curved arms 25 and 25 of diaphragm 21 (Figs. 9 and A circular hole 23 through the center of lever I5 is furnished to accommodate the head of' the central screw 35 which attaches button 3| to diaphragm 21.

`base I by suitable screws I5 and 44 passing through holes-42 and 43. Screws I 8 and 44 with washers 45 and 45 respectively, serve to hold the diaphragm 21 securely in place on the base I. When so positioned, the curved arms 25 and 25 will engage the ears 22 and 23 of the lever I5 and may be joined thereto by soldering or by any other means.

. Screw passing through hole 45 in diaphragm 21, with the aid of a suitable washer and a spacer 41, secures button 3| to diaphragm 21 but in spaced relation thereto, and so positioned that a portion of button 3l will project outwardly through aperture 49 in base I.

Cover 2 is equipped with a pair of suitable conductors 50 and 50'. These conductors pass through the'top of the cover 2 and' turned over ends such as those shown at 5I and 52 of conductor 50, serve to hold the conductors firmly in place. The upper portion of cover 2 is equipped with a recess having inwardly turned lips 55 and 51 under which a suitable terminal block may be inserted to make contact with conductors 50 and 50'.

Contact strips 50 and 5| are designed so that the right ends thereof (Figs. 1 to 3) will make contact with the left ends of conductors 50 and 50 when the cover is in place. Strips 50 and 5I are attached to the upper side of block 8 with screws III and II respectively. At the left end of the strips as viewed in Figs. 1 to 3, they are' turned downwardly and each is formed into a terminal 53 and 54 to which the conductors from the crystal 4 are connected by soldering or otherwise.

When an electric current is sent through. the conductor 50, it is transmitted through the strips 50 and 5I to the piezo-electriccrystal 4, which is put in motion. This motion takes the form of a vibration having its maximum amplitude at the free end of the crystal (the right hand end as Viewed in Figs. v1 to 3). This movement is communicated to lever I5 through the flexible springs tudinal motion of the crystal is not communicated to the lever I5 because of the flexibility of arms 35 and 35, and in like manner, the longitu-` dinal motion of lever I5 is not communicated diaphragm 21 because of the yflexibility of arms 25 and 25 so that the vibratory movement imparted to button 3| is a straight line movement at right angles to the plane of the base I.

The low frequency response of a piezo-electric crystal clamped at one end as described herein, can be increased by the addition of a weight on the free end thereof.- However, this is accomplished at some sacrifice to the high frequency response because the additional weight increases the mechanical inertia of the vibrating crystal. In the present application, I have shown a crystal of tapered form, which construction results in an increase in the low frequency response without any loss of high frequency response. This is accomplished by constructing the crystal with an increasing taper extending from the clamped end thereof toward the free end. A crystal so formed has less stiffness thanfa rectangular crysstal, and this increases the ratio of mass to stiflness without increasing the mechanical inertia of the system. Looking at Fig. 1, it is seen that the crystal 4 tapers from the end which is clamped between the blocks 1 and 8 toward the free end increasing in width from the clamped end toward the free end.

I wish it to be understood that I do not limit lmyself to the exact details of construction shown and described, as my invention is obviously capable of various modifications.

Iclaim: 1. In a hearing aid device, a base,` a piezo-electric crystal mounted on said base with one end free to vibrate, a lever connected to said base and` crystal, a diaphragm attached to said lever and a button connected to said diaphragm.

2. In a hearing aid device, a base, a piezo-elec- I lever are near each other, flexible means for joining the free ends of said crystal and lever together, a diaphragm, means forconnecting said diaphragm to said lever near the mid-point thereof, and a button on said diaphragm designed to transmit the vibration of said crystal to the load.

3. In a hearing aid device, a base, a piezo-electric crystal, means for clamping one end of said crystal to said base while maintaining them in substantially parallel relationship, a lever attached at one end thereof -to said base and arranged in substantial parallelism with said base and crystal, a exible member joining the free ends of said lever and crystal together, a diaphragm connected to said lever and a button on said diaphragm.

4. In a hearing aid device, a base, a piezo-electric crystal mounted on said base with one e'nd free to vibrate, a flexible diaphragm, a button on said diaphragm adapted to communicate witha load, a lever for connecting said crystal and diaphragm so that vibratory movement of the crystal may be communicated to the latter.

5. In a hearing aid device, a base, a piezo-electric crystal mounted on said base so that one end thereof is free to vibrate, a lever vconnected to the free end of said crystal, a flexible diaphragm -connected to said lever and a button connected to said diaphragm and adapted to communicate vibration of said diaphragm toa load.

6. In a hearing aid device, a base, a piezo-elec.- tric crystal mounted on said 4base so that one end .t button on said diaphragm adapted to communicate vibration of said diaphragm to a load.

7. In a hearing aid device, a base, a piezo-electric crystal with one end clamped to said base' and the other end free vibrate, a lever disposed in substantial parallelism with said crystal and having correspondingl ends clamped and free, a connection between the free ends of said crystal and lever which is flexible in a direction parallel to the longitudinal axis of said fcrystal, a diai phragm, a connection between said lever and diaphrlim which is flexible in a direction parallel to the axis of said diaphragm and adapted to coms .municate vibration thereof to a suitable load.

B. In a hearing aid device, a. base, a tapered piezo-electric crystal, means for mapping the narrow end of said crystal to said base, a button 'extending through said base and adapted to carry a load, and means for connecting;r the free end of said crystal and said biiitizm.4 

